Its worth mentioning that VY Canis Majoris has a mass of "only" 17 Solar masses (+-8). This means it has a very low density.
"Despite the mass and very large size, VY CMa has an average density of 5.33 to 8.38 mg/m3 (0.00000533 to 0.00000838 kg/m3), it is over 100,000 times less dense than Earth's atmosphere at sea level (1.2 kg/m3). " [0]
Often these huge but low density objects are incorrectly rendered like our Sun with a "hard" surface. I think it's a pity because they are even weirder and more fascinating objects than that.
The Mote in God's Eye had an interesting description of a star like that, including a starship going fairly deep into it and mentioning that the transition was barely noticable.
How is that possible? And how can that be determined? I'm both intrigued and in disbelief. Does it not collapse due to internal pressure from fusion reactions? Is that just heat, or radiation pressure too? Have I just answered my own questions?
It's important to note that the average density is low, it doesn't mean it's uniformly that dense. I cannot speak for this star in particular, but a lot of variable stars expand and contract so fast that material actually bounces off of it sending out a shell that may or may not re-coalesce or continue going off into space. The shell continues to glow due to the heat it already had, and the heat it receives from the main part of the star.
"Despite the mass and very large size, VY CMa has an average density of 5.33 to 8.38 mg/m3 (0.00000533 to 0.00000838 kg/m3), it is over 100,000 times less dense than Earth's atmosphere at sea level (1.2 kg/m3). " [0]
Often these huge but low density objects are incorrectly rendered like our Sun with a "hard" surface. I think it's a pity because they are even weirder and more fascinating objects than that.
[0] https://en.wikipedia.org/wiki/VY_Canis_Majoris